As Haasman says, it can be done without removing the thermostat housing. Your best bet is to get a good brand stub hose such as one you'd get from the dealer. Generic branded hoses don't always fit well.

You can wrestle the old hose off but it's simpler to cut it off.

Give the new hose a hot bath to make it flexible then apply silicone lube (not petroleum based lube!) to the insides of the hose and the pipe extending from the head. With luck, you'll be able to wrestle the new hose into place. If not, others have trimmed as much as a half inch off the pipe that extends from the head without causing leaks. Debur the pipe so you don't tear the new hose. Don't forget to get the clamps on the pipe before fitting the new hose!

Good luck.

Sixto
95 S420
87 300SDL